API User Experience or, in short, APIUX is the experience that any user interacting with your API will feel. It includes not only the developers writing code that integrates with your API but also end-users that are using your API indirectly through third-party applications. As you will see, the way you design your API has a profound impact on the way even end-users experience an application that consumes your API.
Your API’s User Experience can be broken down into developers and third-party application end users. Let’s explore how these two groups might be affected by your design decisions. Developers are the ones that will feel the most from your design decisions because they will have to write the code that integrates with your API. If your API is hard to integrate with, then developers will have a hard time.
But third-party application end users will also be affected by your design decisions. In this case, you won’t be affecting their experience integrating with your API but instead their experience using the third-party application. Their experience might change for the worse if your design approach introduces friction. Common causes for increased API friction include the API being too chatty or requiring too many round trips to complete an operation and having common operations take many API calls to complete. In both cases, users might notice that the third-party application is feeling slow to use.